<template>
  <div class="list">
    <section>
      <div class="list-l" ref="left">
        <ul class="l-item">
          <li
            v-for="(item, index) in leftData"
            :key="index"
            :class="{ active: index == currentIndex }"
            @click="goScroll(index)"
          >
            {{ item.name }}
          </li>
        </ul>
      </div>

      <div class="list-r" ref="right">
        <div>
          <ul v-for="(item, index) in rightData" :key="index" class="shop-list">
            <li v-for="(k, i) in item" :key="i">
              <div class="elipse">
                <h2>{{ k.name }}</h2>
              </div>
              <ul class="r-content">
                <li v-for="(j, idx) in k.list" :key="idx">
                  <img :src="j.imgUrl" alt="" />
                  <span>{{ j.name }}</span>
                </li>
              </ul>
            </li>
          </ul>
        </div>
      </div>
    </section>
    <Tabbar></Tabbar>
  </div>
</template>

<script>
import BetterScroll from "better-scroll";
import Tabbar from "@/components/common/Tabbar.vue";
import http from "@/common/api/request.js";
export default {
  name: "List",
  data() {
    return {
      isShow: true,
      leftData: [], //左侧数据
      rightData: [], //右侧数据
      rightBScroll: "", //右侧滑动BScroll
      allHeight: [], //承载右侧每一块的高度值
      scrollY: "", //右侧滚动距离
    };
  },
  computed: {
    currentIndex() {
      return this.allHeight.findIndex((item, index) => {
        return this.scrollY >= item && this.scrollY < this.allHeight[index + 1];
      });
    },
  },
  components: {
    Tabbar,
  },
  async created() {
    let res = await http.$axios({
      url: "/api/goods/list",
    });

    let leftArr = [];
    let rightArr = [];

    res.forEach((v) => {
      leftArr.push({
        id: v.id,
        name: v.name,
      });
      rightArr.push(v.data);
    });
    this.leftData = leftArr;
    this.rightData = rightArr;

    this.$nextTick(() => {
      //左侧滑动
      new BetterScroll(this.$refs.left, {
        click: true,
        bounce: false,
      });
      //右侧滑动
      this.rightBScroll = new BetterScroll(this.$refs.right, {
        click: true,
        probeType: 3,
        bounce: false,
      });
      //统计右侧所有板块高度值，并且放入数组中
      let height = 0;
      this.allHeight.push(height);
      //获取右侧每一块高度
      let uls = this.$refs.right.getElementsByClassName("shop-list");
      //把dom对象转换成功真正的数组
      Array.from(uls).forEach((v) => {
        height += v.clientHeight;
        this.allHeight.push(height);
      });
      //得到右侧滚动的值
      this.rightBScroll.on("scroll", (pos) => {
        this.scrollY = Math.abs(pos.y);
        if (Math.abs(pos.y) >= 50) {
          this.isShow = false;
        } else {
          this.isShow = true;
        }
      });
    });
  },
  methods: {
    goScroll(index) {
      this.rightBScroll.scrollTo(0, -this.allHeight[index], 300);
    },
  },
};
</script>
<style scoped lang='scss'>
.list {
  display: flex;
  flex-direction: column;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}
section {
  display: flex;
  flex: 1;
  overflow: hidden;
}
.list-l {
  width: 2.48rem;
  background-color: #fff;
  border-right: 1px solid #cccccc;
  overflow: hidden;
  .l-item {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    li {
      width: 100%;
      padding: 0.08rem 0;
      margin: 0.533333rem 0;
      text-align: center;
      font-size: 0.373333rem;
      &.active {
        color: #6cf;
        border-left: 6px solid #6cf;
      }
    }
  }
}

.list-r {
  flex: 1;
  overflow: hidden;
  .shop-list {
    text-align: center;
    .elipse {
      margin: 0 auto;
      margin-top: 10px;
      width: 100px;
      height: 20px;
      border-radius: 10px;
      background-color: rgba(14, 212, 202, 0.2);
      display: flex;
      align-items: center;
      justify-content: center;
      h2 {
        position: absolute;
        padding: 0.533333rem 0;
        font-size: 16px;
        font-weight: 300;
      }
    }
    .r-content {
      display: flex;
      flex-wrap: wrap;
      li {
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        width: 33.33%;
        padding: 0.266666rem 0;
        img {
          width: 1.413333rem;
          height: 1.413333rem;
        }
        span {
          font-size: 0.426666rem;
        }
      }
    }
  }
}
::v-deep.tabbar {
  border-top: 1px solid #cccccc;
}
</style>


